CN220739363U - Closing-in core rod for forging - Google Patents

Abstract

The utility model provides a closing-in core rod for forging, and relates to the technical field of forging. The mandrel comprises a mandrel main body formed by three sections of rod bodies, wherein the three sections of rod bodies are a first section of rod body, a second section of rod body and a third section of rod body which is connected between the two sections of rod bodies and is in a truncated cone shape, so that the shape of the mandrel main body is similar to the shape of an inner hole of a main shaft to be processed on the whole, and therefore, when the mandrel is inserted into the inner hole of the main shaft to be subjected to closing forging, the required inner hole can be formed by one-step forging without replacing straight mandrels with different specifications; meanwhile, the diameters of the first section and the second section of the rod body of the mandrel are obtained by subtracting the same forging allowance from the diameters of the second inner hole and the first inner hole of the main shaft, so that the uniform distribution of the whole forging allowance of the inner hole of the main shaft can be ensured, the movement of the blank in the diameter direction is restrained, and the concentricity of the inner hole of the closing-in part is ensured during the whole forging of the main shaft.

Description

Closing-in core rod for forging

Technical Field

The utility model relates to the technical field of forging, in particular to a closing-in core rod for forging.

Background

A hydro-electric main shaft is a shaft that connects the turbine runner with the generator rotor for torque transfer. Forging is a process of applying pressure to a metal blank by a forging machine to plastically deform the metal blank to obtain a forging having certain mechanical properties, shape and size. For some convergent hydroelectric spindles, convergent forging is generally required. The term "neck forging" refers to reducing the internal dimensions of a portion or portions of a hollow forging.

The traditional forging of the hollow closing-in hydroelectric spindle generally adopts a split forging mode, namely, the hollow closing-in hydroelectric spindle is segmented into an upper flange, a spindle body and a lower flange, and each segment is respectively and independently forged and processed and then assembled and welded into an integral spindle. However, when the closing-in main shaft is forged in a split mode, each section needs to be lengthened in the length direction, performance samples are reserved, the upper flange and the lower flange can only be forged according to ring parts, the utilization rate of materials is extremely low, and the production cost is high. The method of integral forging forming is carried out by replacing the straight core rods with different specifications during forging, certain displacement exists in the front and rear forged parts of the core rods with different specifications inevitably due to the fact that the specifications of the used core rods are different, and particularly, the concentricity of an inner hole is not easy to guarantee due to the fact that the main shaft with the larger inner hole machining diameter drop is used, forging auxiliary time is greatly increased due to the fact that multiple core rods are used, closing-in forming with the large inner hole drop is completed by multiple times, and the problems that forming allowance is large, closing-in end inner hole forming is not in place and the like exist.

Disclosure of Invention

The utility model aims to solve the problems that for the hollow closing-in hydroelectric spindle, the utilization rate of the split forging material is extremely low, the production cost is high, the conventional integral forging forming needs to replace straight core rods with different specifications, and the quality problems of large machining allowance, incomplete inner hole forming, incapability of ensuring the concentricity of the inner hole and the like exist.

In order to solve at least one aspect of the above problems, the present utility model provides a closing-in mandrel for forging, which is used for closing-in forging of a hollow hydropower spindle, wherein an inner hole of the hollow hydropower spindle comprises a second inner hole, a third inner hole and a first inner hole, the third inner hole is a conical hole, one end of the third inner hole with smaller diameter is connected with the second inner hole, and one end of the third inner hole with larger diameter is connected with the first inner hole;

the closing-in core rod for forging comprises a core rod main body, wherein the core rod main body comprises a second section of rod body, a third section of rod body and a first section of rod body which are sequentially connected, the third section of rod body is in a round table shape, the small end of the third section of rod body is connected with the second section of rod body, the large end of the third section of rod body is connected with the first section of rod body, the diameter of the second section of rod body is the difference between the diameter of the second inner hole and the forging allowance, and the diameter of the first section of rod body is the difference between the diameter of the first inner hole and the forging allowance.

Preferably, the maximum diameter of the third segment rod body is the difference between the diameter of the first segment rod body and a first preset value, the first preset value is 50-100mm, a first chamfer is arranged between the outer wall of the third segment rod body and the outer wall of the second segment rod body, a second chamfer is arranged between the outer wall of the third segment rod body and the outer wall of the first segment rod body, and the radius of the second chamfer is two to three times that of the first chamfer.

Preferably, the axial length of the mandrel main body at the third section of the mandrel main body is the same as the axial length of the hollow hydropower spindle at the third inner hole.

Preferably, the axial length of the mandrel main body at the first section of the mandrel body is equal to the sum of the maximum value of the shaft length of the hollow hydropower spindle at the first inner hole and the forging allowance.

Preferably, the closing-in core rod for forging further comprises a fixing ring, a clamping groove is formed in the outer circumferential wall of one end, far away from the third section of rod, of the first section of rod, and the fixing ring is used for being arranged in the clamping groove.

Preferably, the clamping grooves comprise a plurality of clamping grooves, the clamping grooves are sequentially distributed on the outer wall of the first section of rod body along the axial direction parallel to the first section of rod body, and the fixing ring is used for being connected with one of the clamping grooves so as to be used for forging hollow hydropower spindles with different length specifications.

Preferably, the diameter of the first section of rod body at the clamping groove is the difference between the diameter of the first section of rod body and a second preset value, and the second preset value is 80-100mm.

Preferably, the fixing ring comprises two half rings, the thickness of each half ring is the difference between the width of the clamping groove and a third preset value, the third preset value is 3-5mm, the inner diameter of each half ring is half of the diameter of the first section of rod body at the clamping groove, and the outer diameter of each half ring is larger than or equal to the outer diameter of the shaft body of the hollow hydropower spindle at the second inner hole.

Preferably, the axial length between one end of the first section bar body, which is close to the third section bar body, and the clamping groove provided with the fixing ring is a positioning length, and the positioning length is the sum of the length of the shaft of the hollow hydropower spindle at the first inner hole and the forging allowance.

Preferably, a blind hole is formed in the central axis of the mandrel main body, and the blind hole is used for being connected with the cooling device.

Compared with the prior art, the closing core rod for forging has the advantages that:

the closing-in core rod comprises a core rod main body formed by three sections of rod bodies, wherein the three sections of rod bodies are a first section of rod body, a second section of rod body and a third section of rod body which is connected between the two sections of rod bodies and is in a circular truncated cone shape, so that the shape of the core rod main body is similar to the shape of an inner hole of a main shaft to be processed on the whole; meanwhile, the diameters of the first section and the second section of the rod body of the mandrel are obtained by subtracting the same forging allowance from the diameters of the second inner hole and the first inner hole of the main shaft, so that the uniform distribution of the whole forging allowance of the inner hole of the main shaft can be ensured, the movement of the blank in the diameter direction is restrained, and the concentricity of the inner hole of the closing-in part is ensured during the whole forging of the main shaft.

Drawings

FIG. 1 is a schematic view of a hollow water spindle in an embodiment of the present utility model;

FIG. 2 is a schematic illustration of the forging position being displaced when the mandrel is drawn out using different gauges;

FIG. 3 is a schematic view showing a structure of a closing-in mandrel for forging according to an embodiment of the present utility model;

FIG. 4 is a schematic cross-sectional view taken along the direction A-A in FIG. 3;

FIG. 5 is a side view of a half ring in an embodiment of the utility model;

FIG. 6 is a schematic cross-sectional view taken along the direction B-B in FIG. 5;

fig. 7 is a schematic view of the gas cutting and shoulder cutting of the ingot in the ingot making operation before closing in;

fig. 8 is a schematic diagram of the punching of steel ingots in a bloom operation prior to necking;

FIG. 9 is a schematic view of a stepped cylinder obtained by drawing a blank with a straight mandrel in a blank-making operation prior to necking;

FIG. 10 is a schematic view of the stepped cartridge of FIG. 9 flattened;

FIG. 11 is a schematic diagram of the forging of the N part of the stepped cylinder to obtain the V and IV parts of the main shaft in the blank making operation before closing;

FIG. 12 is a schematic view of the forging of the resulting spindles II, III in the preform operation prior to necking;

FIG. 13 is a schematic structural view of a forged part after close-up forging.

Reference numerals illustrate:

10-an upper flange; 20-shaft body; 30-a lower flange; 100-a closing core rod for forging; 1-a first section bar body 1; 2-a second section bar body 2; 3-a third section bar body 3; 4-a clamping groove 4; 5-a fixing ring 5; 51-half ring; 6-blind holes; 7-a bolt; 8-hollow punch.

Detailed Description

As shown in FIG. 1, the hollow necking hydroelectric spindle made of 20SiMn material is structurally schematic, and consists of five parts, namely a necking flange I, a necking flange V, a straight barrel II, a straight barrel IV and a shaft collar III. It can be seen that the hollow necking hydropower spindle comprises a step inner hole, and the processing diameter drop of the inner hole is larger, so that the hollow necking hydropower spindle made of 20SiMn materials is forged in a traditional mode of being divided into three sections of an upper flange 10, a spindle body 20 and a lower flange 30, but the utilization rate of the split forged materials is extremely low, and the production cost is high. The defect of split forging can be overcome by replacing straight core rods with different specifications for integral forming during forging, but the conventional integral forging forming mode has the quality problems that the forming allowance is large, the inner hole of the closing end is formed in place, the concentricity of the inner hole cannot be ensured, the outer circle diameter is locally drawn and is not machined enough, and the like. Particularly, if the flange diameter (phi D1) is more than phi 2300mm and the inner hole processing drop (phi D1-phi D2) is more than 650mm, if the straight core rods with different specifications are replaced during forging to perform conventional integral forging forming, besides the forming problem is caused, the core rods with different specifications are adopted for drawing the two ends of the main shaft, and the later used smaller core rods cannot be positioned with the blank mutually, so that the blank is in a free shaking state (as shown in fig. 2) in the diameter direction, a certain displacement delta R exists in the front-back forging positions of the core rods with different specifications inevitably, the concentricity of the inner diameter and the outer diameter cannot be ensured, and the core rods are easy to lock. The difference between the specifications of the core rods used before and after the forging is reduced, the displacement delta R can be reduced only to a limited extent, the number of the core rods put into use is increased, the forging auxiliary time is also greatly increased, the closing-up forming of the large drop of the inner hole needs to be completed with multiple times of forging, and the quality risk of coarse grains of the forging piece can be increased due to the fact that the forging is carried out for multiple times without forging at high temperature.

In summary, for the forging of the hollow closing-in main shaft as shown in fig. 1, since the split forging has many defects of low material utilization rate, high cost and the like caused by reserving samples for each section, the related art tends to adopt an integral forging method, but the difficulty of integral near net forming forging is extremely high, and the near net forming refers to a forming technology of mechanical parts after forming the parts, which only needs a small amount of processing or no processing. However, conventional integral forging has a large drop in the diameter of the inner hole of the hollow closed-end hydroelectric spindle to be machined, so that the straight core rods with different specifications need to be replaced during forging, but the method has a plurality of defects. The utility model provides a special core rod for the closing forging of a main shaft, which aims to solve the problem of integral forging of a hollow closing hydroelectric main shaft.

In order that the above objects, features and advantages of the utility model will be readily understood, a more particular description of the utility model will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings.

The closing-in core rod for forging (hereinafter referred to as core rod for short) is used for closing-in forging of a hollow hydropower main shaft (hereinafter referred to as main shaft for short), wherein an inner hole of the hollow hydropower main shaft comprises a second inner hole, a third inner hole and a first inner hole, the third inner hole is a conical hole, one end of the third inner hole with smaller diameter is connected with the second inner hole, and one end of the third inner hole with larger diameter is connected with the first inner hole;

the closing-in core rod 100 for forging comprises a core rod main body, wherein the core rod main body comprises a second section of rod body 2, a third section of rod body 3 and a first section of rod body 1 which are sequentially connected, the third section of rod body 3 is in a round table shape, the small end of the third section of rod body 3 is connected with the second section of rod body 2, the large end of the third section of rod body 3 is connected with the first section of rod body 1, the diameter of the second section of rod body 2 is the difference between the diameter of the second inner hole and the forging allowance, and the diameter of the first section of rod body 1 is the difference between the diameter of the first inner hole and the forging allowance.

Unlike the conventional straight core rod having a uniform diameter, the core rod of the present embodiment, as shown in fig. 3, includes a core rod body composed of three segments, wherein the first and third segments 3 have a shape similar to the shape of the inner holes (i.e., the second inner hole and the third inner hole) of the i-portion closing-in flange of the main shaft in fig. 1, and specifically, as shown in fig. 1, the main shaft to be finally processed has the second inner hole having a uniform diameter, the third inner hole having a uniform variation in diameter, and the first inner hole having a uniform diameter, which is required to be obtained by closing-in forging. As shown in fig. 3, the mandrel in this embodiment has a second segment of rod body 2 having a uniform diameter, a third segment of rod body 3 having a uniform diameter, and a first segment of rod body 1 having a uniform diameter, and thus the outer shape of the mandrel body is said to be similar to the shape of the inner bore of the main shaft. The outer shape of the core rod is set to be similar to the inner hole of the main shaft, when the blank is subjected to necking operation, the core rod is directly inserted into the V part of the blank, the necking reduction is controlled, the reduction of each circle is guaranteed to be uniform, the core rod exits the blank after the inner hole of the I part of the blank is basically attached to the outer surface of the core rod, and therefore a second inner hole, a third inner hole and a first inner hole as shown in fig. 1 are machined at the inner hole of the blank, and the whole necking forging of the main shaft is completed.

In this embodiment, the diameter Φd2″ of the second segment rod body 2 of the mandrel is Φd2=Φd2—the forging allowance M, and the diameter Φd1″ of the first segment rod body 1 is Φd1=Φd1—the forging allowance M, wherein Φd1, Φd2 are the diameters of the second inner bore and the first inner bore of the spindle in fig. 1. That is, the diameters of the first section and the second section of the rod body 2 of the mandrel are the diameters of the second inner hole and the first inner hole of the main shaft minus the same forging allowance respectively, and by setting the same forging allowance, the uniform distribution of the whole forging allowance of the inner hole of the main shaft can be ensured, meanwhile, the movement of the blank in the diameter direction is restrained, and the concentricity of the inner hole of the closing-in part is ensured during the whole forging of the main shaft.

In some embodiments, the maximum diameter of the third segment rod 3 is the difference between the diameter of the first segment rod 1 and a first preset value, the first preset value is 50-100mm, a first chamfer is formed between the outer wall of the third segment rod 3 and the outer wall of the second segment rod 2, a second chamfer is formed between the outer wall of the third segment rod 3 and the outer wall of the first segment rod 1, and the radius R2 'of the second chamfer is two to three times the radius R1' of the first chamfer.

In this embodiment, the maximum diameter Φd3 ' =Φd1 ' - (50-100) mm of the third segment of the rod body 3 of the mandrel is designed so that the mandrel can be smoothly pulled out after the end of the closing forging, and the surface of the mandrel can be smoothly transited by R2 ' =2r1 ' -3R1 ', thereby avoiding stress concentration at the connecting position of the third segment of the rod body 3 and other two rod bodies during the forging and affecting the overall strength of the mandrel. Therefore, the whole outer circle of the core rod of the embodiment has a variable taper design, so that the core rod can be smoothly pulled out after the closing-in while the machining allowance of the inner hole of the main shaft is reduced.

In some embodiments, the axial length of the mandrel body at the third section bar body 3 is the same as the shaft length of the hollow hydro-power main shaft at the third inner hole.

As shown in fig. 3, the axial length of the core rod main body at the third section of the rod body 3 is L2 ', the axial length of the main shaft at the third inner hole is L2 in fig. 1, and in this embodiment, the length dimension L2' of the core rod is designed to be the same as the length dimension L2 of the main shaft, so that the appearance and dimension of the core rod are attached to those of the main shaft target inner hole processing, which is beneficial to inserting the core rod into the main shaft inner hole for closing forging, and the required inner hole is formed by one-step forging without replacing the core rods with different specifications.

In some embodiments, the axial length of the mandrel body at the first segment of the mandrel body 1 is the sum of the forging allowance and the maximum value of shaft lengths of the hollow hydro-power main shaft at the first inner hole.

As shown in fig. 3, the axial length of the mandrel body at the first segment of the mandrel body 1, i.e., L, and the axial length of the main shaft at the first bore in fig. 1 is L1. It should be noted and understood that, considering the adaptability of the spindle, the spindle generally has different length specifications, so for the hollow necking spindle shown in fig. 1, multiple specifications can be generated due to the different lengths of the straight barrel sections of the spindle at the first inner hole, so in the same kind of spindle, the lengths of the spindle bodies at the first holes also have multiple sizes, and the maximum size of the lengths of all the spindle bodies at the first inner hole in the same kind of spindle is denoted as L1max. In this embodiment, considering the adaptability of the forging spindle, the length dimension L of the mandrel is designed to cover all spindles of the same type of specification, so that the design is performed according to the maximum length L1max of the spindle L1 of the same type of specification, i.e., l=l1max+the forging allowance M. Therefore, when the necking forging is carried out, the mandrel is inserted into the inner hole of the main shaft, so that the mandrel can be ensured to have enough length by the design, the applicability of the mandrel is improved, and the necking forging of the main shaft with different length specifications can be applied.

In some embodiments, the mandrel further comprises a fixing ring 5, a clamping groove 4 is arranged on the circumferential outer wall of one end of the first segment of the mandrel body 1, which is far away from the third segment of the mandrel body 3, and the fixing ring 5 is used for being arranged in the clamping groove 4.

In this embodiment, a clamping groove 4 is formed in the outer wall of the end portion of the first segment of the rod body 1, and a fixing ring 5 is arranged in the clamping groove 4, so that when the mandrel is used for closing forging, the mandrel is inserted into an inner hole of a blank until the fixing ring 5 on the mandrel is attached to the blank, the clamping groove 4 and the fixing ring 5 connected with the mandrel limit the blank to freely move in the axial direction together, and meanwhile, the clamping groove plays an axial positioning role on the closing position during forging, so that the axial forging allowance of the closing position can be greatly reduced.

In some embodiments, the clamping grooves 4 include a plurality of clamping grooves 4, the plurality of clamping grooves 4 are sequentially distributed on the outer wall of the first section bar body 1 along the axial direction parallel to the first section bar body 1, and the fixing ring 5 is used for being connected with one of the clamping grooves 4 so as to be used for forging hollow hydropower spindles with different length specifications.

As shown in fig. 3, a plurality of clamping grooves 4 are formed in the outer wall of the end part of the first section of rod body 1, three clamping grooves 4 are shown in the figure, and the same mandrel can be used for forging closing-in spindles with different length specifications by designing different clamping grooves 4. It can be understood that the clamping groove 4 and the fixing ring 5 thereon mainly play the roles of axial positioning and limiting, so that for spindles of different length specifications, the fixing ring 5 can be installed on the clamping groove 4 at different positions, thereby improving the applicability of the core rod and being suitable for the closing forging of spindles of various specifications.

In some embodiments, the diameter of the first segment rod body 1 at the clamping groove 4 is a difference between the diameter of the first segment rod body 1 and a second preset value, and the second preset value is 80-100mm.

It can be understood that the outer wall of the mandrel main body is provided with the clamping groove 4, the clamping groove 4 has a certain depth, and the diameter of the first section of the mandrel body 1 minus twice the depth of the clamping groove 4 is the diameter of the first section of the mandrel body 1 at the clamping groove 4, and the second preset value is twice the depth of the clamping groove 4, so in this embodiment, the depth of the clamping groove 4 is 40-50mm.

In some embodiments, the fixing ring 5 includes two half rings 51, the thickness of the half ring 51 is the difference between the width of the clamping groove 4 and a third preset value, the third preset value is 3-5mm, the inner diameter of the half ring 51 is half of the diameter of the first section of rod body 1 at the clamping groove 4, and the outer diameter of the half ring 51 is greater than or equal to the shaft outer diameter of the hollow hydropower spindle at the second inner hole.

As shown in fig. 4, two half rings 51 in a split structure form are connected by two bolts 7 at the position of a clamping groove 4 to form a fixed ring 5, the two half rings 51 are identical in size, the structure is shown in fig. 5 and 6, the thickness H3=L5- (3-5) mm of the half rings 51, the inner diameter Rr5=d5 '/2 of the half rings 51, the outer diameter R6 of the half rings 51 is equal to or larger than D1/2, wherein L5 is the width of the clamping groove 4, D5' is the diameter of the first section bar body 1 at the clamping groove 4, and D1 is the shaft outer diameter of the hollow hydropower spindle at the second inner hole. The fixing ring 5 which is formed by surrounding the semi-rings 51 with the size can realize the axial limit of the blank and avoid the clamping in the clamping groove 4 so as not to be easy to take out.

In some embodiments, the two half rings 51 are connected by fasteners such as bolts 7, the half rings 51 comprise a ring body and bosses arranged at two ends of the ring body, bolt holes are arranged on the bosses, and the two half rings 51 are used for connecting the bosses of the two half rings 51 together by the fasteners such as bolts 7, so that the two half rings 51 are assembled into the fixing ring 5. The height of the boss is H1, the length of the boss is L8, the width of the boss is the same as the thickness H3 of the half ring 51, the diameter phi d 4= 0.4H3 of a bolt hole on the boss, the too large influence on the strength of the boss of the half ring 51 is avoided, the design L8 is more than or equal to 2d4, and under the premise that the closing of a bolt is not influenced, the H1 is as large as possible so as to ensure that the two half rings 51 are connected to form the fixing ring 5 to have higher stability when forging impact.

In some embodiments, the half ring 51 further has an eccentricity h2=1-3 mm, it can be understood that a circle of clamping groove 4 is formed on the circumferential side wall of the first segment rod body 1, two half rings 51 are installed in the clamping groove 4, the half rings 51 occupy half of the circumferential side surface of the first segment rod body 1, theoretically, a connecting line between two ends of the half rings 51 should pass through the center of the first segment rod body 1, and a line parallel to two ends of the half rings 51 and passing through the center of the first segment rod body 1 is called a datum line. In this embodiment, the connecting lines of the two ends of the half ring 51 deviate from the reference line, so that the half ring 51 has an eccentricity, and thus, the tight contact between the fixing ring 5 and the spindle can be ensured, and the bolt is not easy to loosen.

In some embodiments, the axial length between the end of the first segment rod body 1 near the third segment rod body 3 and the clamping groove 4 provided with the fixing ring 5 is a positioning length, and the positioning length is the sum of the shaft length of the hollow hydropower spindle at the first inner hole and the forging allowance.

In this embodiment, the positioning length L1' required for forging the mandrel is designed as: l1 '=spindle length dimension l1+forging margin, whereby the specific clamping groove 4 position for each forging pass can be determined according to the length dimension L1'. As shown in fig. 3, the left end of the first segment rod body 1 is connected with the third segment rod body 3, three clamping grooves 4 are provided on the circumferential side wall of the right end of the first segment rod body 1, the middle clamping groove can be determined to be the clamping groove 4 for forging and necking according to L1 ', a fixing ring 5 is required to be installed on the clamping groove, and as can be seen from fig. 3, L1' is the distance between the left end of the first segment rod body 1 and the inner side wall of the middle clamping groove, and the inner side wall of the middle clamping groove refers to the side wall close to the third segment rod body 3.

In some embodiments, a blind hole 6 is provided at the central axis of the mandrel body, and the blind hole 6 is used for connecting with a cooling device.

In this embodiment, a blind hole 6 with a diameter phid0×l4 is machined at the center of the mandrel, as in the example shown in fig. 3, the depth of the blind hole 6 is L4, the diameter phid0 is 200mm, and the blind hole 6 is used for connecting a water pipe during forging to perform water cooling, so that plastic deformation and locking can be prevented during drawing of the mandrel during closing forging.

The process of using the mandrel bar of this embodiment will be described below.

The core rod of the embodiment is used for closing in operation, and blank making operation needs to be completed before closing in.

Illustratively, after steel ingots are vacuum-poured by adopting a VD+LB3 method and gas-cut and blanking of the steel ingots, forging procedures of upsetting, mandrel drawing to form a stepped cylinder, flattening and mandrel drawing are adopted, blanks are sequentially forged and formed according to the sequence of the parts V, IV, III and II of a main shaft in FIG. 1, and the outer diameter of the blank at the part I before closing is kept at a closing-in amount of 1000 mm. Wherein, the steel ingot used is 258T vacuum casting steel ingot, as shown in fig. 7, the steel ingot riser phi 3221mm, the steel ingot water gap phi 2904mm, and the ingot body height hd=3521 mm.

Specifically, (1) preparing 258T vacuum upper-pouring steel ingot by adopting a VD+LB3 method, slagging by lime+fluorite, diffusing and deoxidizing aluminum powder, controlling the content of Mn, si, S, P which is easy to segregate according to the lower limit, and feeding a calcium line before tapping to modify impurities, wherein after feeding the calcium line, the soft blowing time of 10-15 minutes is ensured to fully float Ca deoxidized products. And argon blowing operation is performed on the whole process of the tundish core rod during vacuum casting.

(2) And (3) receiving and hot-feeding the steel ingot, cutting off a nozzle body 150mm (with a knife edge) after ingot feeding, gas-cutting all the dead heads, and carrying out shoulder cutting treatment on the body at the dead head end of the steel ingot, wherein the radial depth of the shoulder cutting is 200mm, and the height of the shoulder cutting is 300mm. In fig. 7, arrow qg indicates that the gas cutting operation is performed therein, and arrow qj indicates that the shoulder cutting operation is performed therein.

(3) After gas cutting, the mixture is put into a trolley type heating furnace for heating, and the temperature is kept between 600 and 650 ℃ for 6 hours and then is increased according to power.

(4) The high-temperature heating and heat preserving temperature is 1270+0-20 ℃, and the high-temperature diffusion treatment is carried out to lighten the dendrite segregation of the steel ingot, and the heat preserving time is more than or equal to 35H. The nozzle end was upset down to a height h=2200 mm and a diameter Φ3790mm, as shown in fig. 8, through holes were punched in one side with a Φ1200mm hollow punch 8 and the ingot core defects were removed.

(5) The heating temperature is 1250+/-10 ℃, and the heat preservation is more than or equal to 24H. The step tube shown in fig. 9 (including M part and N part) was swaged with a 1200mm upper flat lower V anvil, Φ1180mm mandrel drawn out to Φoutside=3350mm, and the total length of the step tube was about 3700mm. And (5) after the mandrel is pulled out, cutting and cleaning punching burrs.

(6) The heating temperature is 1250+/-10 ℃, and the heat preservation is more than or equal to 20H. As shown in fig. 10, the step barrel B is punched down, and the two end surfaces of the barrel are flattened and the barrel is bulged.

(7) The heating temperature is 1250+/-10 ℃, and the heat preservation is more than or equal to 18H. And inserting a core rod with the diameter of phi 1180mm into the B part of the step cylinder, adopting a V anvil with the upper part being flat and the lower part being flat and the core rod being elongated to the outside of phi=2900 mm, blanking according to the drawing of figure 11, and forging out parts V and IV.

(8) The heating temperature is 1250+/-10 ℃, and the heat preservation is more than or equal to 16H. According to the figure 12, a core rod with the diameter of phi 1180mm is inserted into the V part, a V anvil with the upper part being flat and the lower part being flat and the III part being blanked and the II part being forged until the diameter of phi 2050mm is adopted.

(9) And (5) the outer diameter of the hollow part A is up to phi 3200mm, and the preparation of the blank before closing is completed.

Next, a closing forging is performed, and Φd1=Φ1470mm, Φd2=Φ800mm, and an inner hole machining drop (Φd1- Φd2) =670 mm of the final forging spindle. The parameters of the core rod used are as follows: Φd1=Φ1180mm, Φd2=Φ550mm, Φd5=Φ110mm, l1 '=4400 mm, l2=600 mm, l4=5200 mm, h3=200 mm, Φd4=80 mm, rr5=560 mm, h2=2 mm, r1' =100 mm, l8=160 mm, h1=293 mm.

During closing, the core rod is inserted from the V part to close, the closing reduction is controlled according to 100-200mm, the reduction of each circle is required to be ensured to be uniform, the core rod is withdrawn from the blank after the inner hole of the blank at the I part is basically attached to the outer surface of the core rod, and the I part is empty to be collected by the reduction of 50mm. The whole necking process adopts an upper flat lower V-shaped anvil, and a tilting gear is matched with an operating machine to perform rotary forging. The heating temperature of the closing forging is 1250+/-10 ℃, for example, the heating temperature of the incomplete furnace returning after one fire is 1200+/-10 ℃.

Specifically, (1) the v portion is inserted into the special core rod until the fixing ring 5 on the special core rod is attached to the blank. The water pipe is connected with the blind hole 6 of the special core rod for water cooling.

(2) When the special core rod is used for closing up, a 1200mm wide upper flat lower V anvil is used for drawing up the I part. The whole necking process is performed by rotary forging by using a tilting gear and an operating machine, and the rolling planes of the two anvils are basically connected by rolling down the two anvils front and back.

(3) The drawing closing-in rolling reduction of the first three circles is controlled according to 150-200mm, the rolling reduction is as high as possible, and the rolling reduction of each circle needs to be ensured to be basically uniform.

(4) The subsequent turn number of drawing closing-in rolling reduction is controlled according to 100-150mm, the rolling reduction of the part with large gap between the inner hole of the I part blank and the special core rod is selected as the upper limit, and the rolling reduction of the part with small gap between the inner hole of the I part blank and the special core rod is selected as the lower limit.

(5) And (3) drawing until the inner hole of the I blank is basically attached to the outer surface of the special core rod, and then withdrawing the special core rod from the blank.

(6) The manipulator holds the V part, the tilting gear is matched with rotation, the upper flat lower V anvil is continued to empty the I part, the pressing amount is controlled according to 50mm, the V part is empty to be received until the outer diameter size phi 2330mm of the finished product of the I part, meanwhile, a step close to the II part is forged, and the closing-in is finished.

(7) After closing in, the forging size is shown in fig. 13, wherein the broken line represents the final machined shape of the spindle.

Finally, after the closing forging is completed, the forging post-treatment is needed, and the main shaft is placed on a sizing block at a ventilation position, is cooled to 350-400 ℃ in an air mode, is put into a furnace, is put into the furnace to perform positive tempering for refining grains, and is heated to 900-920 ℃ for 12 hours. And after the heat preservation is finished, hanging the forge piece at a well ventilated place for air cooling. Air cooling to 350-400 deg.C, charging into furnace, heating to 590+ -10 deg.C, and preserving heat for 16 hr. And after the heat preservation is finished, cooling to less than 200 ℃ and discharging to finish the integral forging of the hollow closed hydroelectric spindle.

Although the utility model is disclosed above, the scope of the utility model is not limited thereto. Various changes and modifications may be made by one skilled in the art without departing from the spirit and scope of the utility model, and these changes and modifications will fall within the scope of the utility model.

Claims (10)

1. The closing-in core rod for forging is characterized by being used for closing-in forging of a hollow hydropower spindle, wherein an inner hole of the hollow hydropower spindle comprises a second inner hole, a third inner hole and a first inner hole, the third inner hole is a conical hole, one end of the third inner hole with smaller diameter is connected with the second inner hole, and one end of the third inner hole with larger diameter is connected with the first inner hole;

the closing-in core rod for forging comprises a core rod main body, wherein the core rod main body comprises a second section rod body (2), a third section rod body (3) and a first section rod body (1) which are sequentially connected, the third section rod body (3) is in a round table shape, the small end of the third section rod body (3) is connected with the second section rod body (2), the large end of the third section rod body (3) is connected with the first section rod body (1), the diameter of the second section rod body (2) is the difference between the diameter of the second inner hole and the forging allowance, and the diameter of the first section rod body (1) is the difference between the diameter of the first inner hole and the forging allowance.

2. The forging-use closing-in mandrel as recited in claim 1, wherein the maximum diameter of the third-stage rod body (3) is a difference between the diameter of the first-stage rod body (1) and a first preset value of 50-100mm, a first chamfer is provided between the outer wall of the third-stage rod body (3) and the outer wall of the second-stage rod body (2), and a second chamfer is provided between the outer wall of the third-stage rod body (3) and the outer wall of the first-stage rod body (1), and the radius of the second chamfer is two to three times the radius of the first chamfer.

3. A closing-in mandrel for forging according to claim 1, wherein the axial length of the mandrel body at the third segment of the mandrel body (3) is the same as the axial length of the hollow hydro-power spindle at the third inner bore.

4. A closing-in mandrel for forging according to claim 1, wherein the axial length of the mandrel body at the first segment of the mandrel body (1) is the sum of the forging allowance and the maximum value of shaft lengths of the hollow hydro-power main shaft at the first inner hole.

5. The forging necking core rod according to claim 1, further comprising a fixing ring (5), wherein a clamping groove (4) is formed in the outer circumferential wall of one end, far away from the third section of the rod body (3), of the first section of the rod body (1), and the fixing ring (5) is used for being arranged in the clamping groove (4).

6. The necking core rod for forging according to claim 5, wherein the clamping grooves (4) comprise a plurality of clamping grooves (4) which are sequentially distributed on the outer wall of the first section of rod body (1) along the axial direction parallel to the first section of rod body (1), and the fixing ring (5) is used for being connected with one clamping groove (4) so as to forge hollow hydropower spindles with different length specifications.

7. The forging-purpose closing-in mandrel as recited in claim 5, wherein the diameter of the first-stage rod body (1) at the clamping groove (4) is a difference between the diameter of the first-stage rod body (1) and a second preset value, the second preset value being 80-100mm.

8. The necking mandrel for forging according to claim 7, characterized in that the fixing ring (5) comprises two half rings (51), the thickness of the half rings (51) is the difference between the width of the clamping groove (4) and a third preset value, the third preset value is 3-5mm, the inner diameter of the half rings (51) is half the diameter of the first section of rod body (1) at the clamping groove (4), and the outer diameter of the half rings (51) is larger than or equal to the shaft outer diameter of the hollow hydropower spindle at the second inner hole.

9. The closing-in mandrel for forging according to claim 5, wherein an axial length between an end of the first segment rod body (1) close to the third segment rod body (3) and the clamping groove (4) to which the fixing ring (5) is attached is a positioning length, and the positioning length is a sum of a shaft length of the hollow hydropower spindle at the first inner hole and the forging allowance.

10. The closing-in mandrel for forging according to claim 1, characterized in that a blind hole (6) is provided at the central axis of the mandrel body, the blind hole (6) being for connection with a cooling device.